Acceleration responsive switch

ABSTRACT

An acceleration responsive switch includes a housing mounting a pair of spaced fixed contacts connected across a source of power. The housing includes a cylindrical lateral extension which slidably receives a pushbutton and a release plate. A coil compression spring seating on one apertured wall of the housing holds the release plate in engagement with the pushbutton to hold the pushbutton in engagement with the other apertured wall. An operator is slidably mounted within a guide portion of the release plate. A movable contact for bridging the fixed contacts is slidably mounted on the operator and spring biased to a position connecting the fixed contacts. A plurality of balls are slidably mounted within respective radial bores of the operator for movement inwardly of the bores or outwardly thereof. In the latter position, the balls are axially engageable between the walls of the bores and a radial shoulder of the release plate to locate the operator in a first position against a spring bias to a second position. The balls are forced outwardly of the bores by an axial pin which is secured to a generally frustoconically shaped seismic mass seating on the release plate. A magnet on the mass exerts a predetermined flux between the mass and plate to normally locate the mass in seated position unless an acceleration pulse of predetermined amplitude and time is applied to the mass. When such a pulse is received, the control pin is withdrawn from engagement with the balls to permit the balls to move inwardly of the bores and release the operator for movement under its spring bias to its second position. The operator engages the movable contact as the operator moves to its second position to open the switch. The switch can be reset in closed position by manually moving the pushbutton inwardly of the extension. This moves the release plate, the mass and the button toward the operator to locate the radial shoulder of the plate with respect to the radial bores of the operator and simultaneously engage the control pin with the balls to force the balls into engagement with such radial shoulder. This reconnects the release plate and operator, and the spring of the release plate returns the operator to its first position and likewise returns the release plate and pushbutton to their normal position to reset the switch.

United States Patent Heckendorf Mar. 14, 1972 [54] ACCELERATIONRESPONSIVE SWITCH Howard A. Heckendorf, Brookfield, Wis.

[73] Assignee: General Motors Corporation, Detroit,

Mich.

22 Filed: July 6,1970

21 Appl.No.: 52,244

[72] inventor:

Primary Examiner-J. V. Truhe Assistant Examiner-George A. MontanyeAttorney-W. E. Finken and Herbert Furman [57] ABSTRACT An accelerationresponsive switch includes a housing mounting a pair of spaced fixedcontacts connected across a source of power. The housing includes acylindrical lateral extension which slidably receives a pushbutton and arelease plate. A coil compression spring seating on one apertured wallof the housing holds the release plate in engagement with the pushbuttonto hold the pushbutton in engagement with the other apertured wall. Anoperator is slidably mounted within a guide portion of the releaseplate. A movable contact for bridging the fixed contacts is slidablymounted on the operator and spring biased to a position connecting thefixed contacts. A plurality of balls are slidably mounted withinrespective radial bores of the operator for movement inwardly of thebores or outwardly thereof. In the latter position, the balls areaxially engageable between the walls of the bores and a radial Ishoulder of the release plate to locatethe operator in a first positionagainst a spring bias to a second position. The balls are forcedoutwardly of the bores by an axial pin which is secured to a generallyfrustoconically shaped seismic mass seating on the release plate. Amagnet on the mass exerts a predetermined fiux between the mass andplate to normally locate the mass in seated position unless anacceleration pulse of predetermined amplitude and time is applied to themass. When such a pulse is received, the control pin is withdrawn fromengagement with the balls to permit the balls to move inwardly of thebores and release the operator for movement under its spring bias to itssecond position. The operator engages the movable contact as theoperator moves to its second position to open the switch. The switch canbe reset in closed position by manually moving the pushbutton inwardlyof the extension. This moves the release plate, the mass and the buttontoward the operator to locate the radial shoulder of the plate withrespect to the radial bores of the operator and simultaneously engagethe control pin with the balls to force the balls into engagement withsuch radial shoulder. This reconnects the release plate and operator,and the spring of the release plate returns the operator to its firstposition and likewise returns the release plate and pushbutton to theirnormal position to reset the switch.

6 Claims, 3 Drawing Figures This invention relates generally toacceleration responsive switches and more particularly to such switcheswhich automatically open a circuit when an acceleration pulse ofpredetermined amplitude and time is received and which can beselectively reset without disassembly.

One of the features of this invention is that it provides an improvedacceleration responsive normally closed switch which includes anoperator movable axially from a normal first position to a secondposition to open the switch, with the operator being normally heldagainst movement by a plurality of balls engaging axially spacedgenerally radially extending cooperating surfaces on the operator and amovable release member, and with the movement of the balls into and outof engagement with the cooperating surfaces being controlled by aseismic mass arrangement. Another feature is that the release member canbe moved relative to the operator when the latter is in second positionto locate the cooperating surfaces in a position to receive the ballstherebetween', with the release member and operator being subsequentlymovable as a unit to return the operator to the first position andpermit the switch to close. A further feature of this invention is thatthe I balls are normally forced outwardly of radial bores in theoperator and into engagement with a radial shoulder of the releasemember by an axially movable pin, the movement of which is controlled bya seismiemass seated on the release member under the action of apredetermined strength magnetic flux which is overcome when anacceleration pulse of predetermined amplitude and time is applied to themass.

These and other features of the switch of this invention will be readilyapparent from the following specification and drawings wherein:

FIG. 1 is a view showing the switch in closed position;

FIG. 2 is a view similar to FIG. 1 showing the switch in open position;and

FIG. 3 is a sectional view taken generally along the plane indicated byline 3-3 of FIG. 2.

Referring now particularly to FIGS. 1 and 2 of the drawings, a switchdesignated generally according to this invention includes a generallyrectangularly shaped baseplate 12 of insulating material and a generallyrectangularly shaped hollow housing 14 of insulating material, thesidewall of which seats on a gasket 16 on the upper surface of plate 12.Diagonally opposite corners of the housing 14 are provided with integrallugs 18 which seat on the gasket 16. Screws, not shown, extend throughapertures in the plate 12 and into such lugs to secure the plate 12 andhousing 14 to each other. Likewise, aligned apertures in such lugs andin the plate provide for mounting of the switch 10 on any suitablesupport, such as a vehicle. The switch 10 of this invention could beused in such a vehicle to disconnect the battery from the electricallyoperated. mechanisms and accessories in the event that the vehiclereceives an acceleration pulse, due to impact or otherwise, whichexceeds a predetermined amplitude and time.

A pair of switch contacts 20 extend through apertures in the upper wallof housing 14 at the other diagonal comers thereof, and each includes anelongated contact portion 22 located along a diagonal through suchothercomers of the housing, and a threaded portion 24 which is secured to theupper wall of the housing by a pair of nuts 26 and a washer 28.

An integral cylindrical extension 30 extends generally normal to theupper wall of housing 14 and including an apertured one end wall 32. Ahollow pushbutton 34 of insulating material is slidably mounted withinthe extension 30. and includes a button portion 36 which extendsoutwardly of the aperture in wall 32 when the pushbutton is in itsposition as shown. A circular metal plate or release member 38 isslidably received in extension 30 and seats against the open end of thepushbutton 34. A coil compression spring 40 seats between plate 38 andan apertured circular plate 42 at the open end of extension 30 andbiases the plate 38 upwardly to in turn bias the pushbutton 34 upwardlyand locate an annular shoulder 44 thereof in engagement with the wall 32adjacent the aperture therein. Any suitable resilient washer can beprovided on the shoulder 44. Plate 42' is held within a counterbore ofextension 30 by contact portions 22.

A cylindrical operator 46 is slidably received within a tubular guide orportion 48 of the plate 38. A split ring spn'ng seat" 50 received withinan intermediate annular groove of the operator seats one end of a coilcompression spring 52, the other end of which seats on the lower surfaceof plate 38 to continually bias the operator 46 downwardly as viewed inFIG. 1. The operator 48 includesthree equally spaced radial bores 54,FIG. 3, which open to a central axial bore of the operator. A ball 56 isslidably received in each bore. When the balls tangentially engage thewalls of the respective boxes and the axially juxtaposed radially andaxially extendingannular shoulder 58 of the plate 38, as shown in FIG.1,. the operator 46- is located in what may be termed its first positionand held against movement by s'pring'52 to its second position shown inFIG. 2. In order for the operator to move to its second or FIG. 2position, balls 56 must move radially inwardly of bores 54 and out oftangential engagement with shoulder 58.

A control pin or member 60 controls the radial movement of the balls 56and is movable relative to the balls within the central axial bore ofthe operator 46. Pin 60 is secured to a hollow seismic mass 62 ofpredetermined weight and of generally frustoconical shape which seats onthe plate 38' and is held thereagainst by an annularpermanent magnet64'which is secured to the mass and exerts a predetermined strength fluxbetween the mass and the plate. The seismic mass 62 normally maintainsthe control pin 60 in its positionas shown in FIG. 1. In this position,the pin 60 tangentially engages the three balls 56 and forces the ballsradially outward of bores 54 into tangential engagement with shoulder 58'to retain the operator 46 in its first position. When the mass issubjected to an acceleration pulse of predetermined amplitude'and time,the mass will tilt relative to the plate 38 to itsposition shown in FIG.2. This movement of the mass partially withdrawsthe pin 60 from theaxial bore of the operator and permits the balls 56 to move radiallyinwardly of the bores 54 and out of engagement with shoulder 58 torelease the operator 46 for movement to its second position shown inFIG. 2. The tapering of the shoulder 58 axially of the operator 46 aidsthe spring 52in camming the balls 56 radially inwardly ofbores 54 topermit movement of the operator to its second position. The guide 48retains the balls within their respective bores as-the operator moves toits second position.

A flanged bushing 66 of insulating material is slidably. mounted ontheoperator 46 and received within a central aperture of the plate 42. Acircular contact 68 seatsagainst the flange of bushing 66 and is heldthereagainst by being piloted on a flanged washer 70 of insulatingmaterial which is slidably mounted on the operator 46 andbiases thecontact 68 upwardly under the action of a coil compression spring 72which seats on thebase of a bore 74 in the plate 12 andalso against thewasher 70.

When the operator 46 is in'its position shown in FIG. 1, the contact 68bridges the contact portions 22 so that the'switch is closed and thecircuit across the switch is complete.

As previously described, when the seismic mass 62 receives anacceleration pulse of predetermined amplitude and time the balls 56willmove inwardly of the operator, and the operator thereupon willimmediately move downwardly to its second position, shown in FIG. 2,under the action of the spring 52. As the operator moves to thisposition, the split ring 50 first engages the bushing 66 and then theplate 42. when the ring 50 engages the bushing 66, it moves the bushing,contact 68 and washer 70 slightly downwardly as shown in FIG. 2.

This moves the contact 68 out of electrical'connection with the contactportions 22 so that the switch is openand the circuit across the switchis open. Upon cessation or reductionof the acceleration pulse, the mass62 will return from its FIG. 2 position to a position in engagement withplate 38, not shown; However, the length of the pin 60 is such that thepin will not engage the balls 56 when the operator is in its secondposition and the mass returns to its normal position.

If it is desired to manually reset the switch, the operator engages thebutton portion 36 and depresses the button 34. This moves the mass 62and the plate 38 downwardly of their position shown in FIG. 2 so thatthe bores 54 now open to the radia] shoulder 58 of the plate 38.Likewise, this moves the control pin 60 into engagement with the balls56 to again force the balls radially outwardly of the bores 54 and intoengagement with the shoulder 58. Thus, the plate 38 and the operator 46are again connected. When the button portion 36 is released, the spring40 immediately returns the plate 38 and mass 62 to their position shownin FIG. 1. The operator 46 moves with the plate 38 to this position topermit spring 72 to locate con tact 68 in electrical contact with thecontact portions 22 and close the switch.

Thus, this invention provides an improved acceleration responsiveswitch.

lclaim:

1. An acceleration responsive switch, comprising, a support including apair of spaced electrical contacts, a release member movably mounted onthe support, means locating the release member in a predetermined firstposition, an operator mounted on the release member for axial movementrelative thereto between first and secondvpositions, means biasing theoperator to the second position, detent means acting between theoperator and release member movable between detented and undetentedpositions and engageable in detented position with the operator to holdthe operator in the first position, a seismic mass movably mounted onthe support, means operatively connecting the mass to the detent meansfor movement of the detent means to undetented position to release theoperator for movement to the second position upon movement of theseismic mass relative to the support, magnetic means exerting a magneticflux of predetermined strength between the mass and support to retainthe seismic mass against movement relative to the support, anacceleration pulse of predetermined amplitude and time moving theseismic mass relative to the support against the flux of the magneticmeans to release the operator, contact means normally electricallyconnecting the spaced contacts, means disconnecting the contact meansand spaced contacts upon movement of the operator to second position,and means for moving the detent means to detented position in engagementwith the operator upon movement ofthe release member from thepredetermined first position when the operator is in the secondposition.

2. The switch recited in claim 1 wherein the locating means for therelease member includes resilient means holding the release memberagainst stop means on the support, the resilient means returning therelease member to the predetermined first position thereof as a unitwith the release member upon movement of the detent means to detentedposition in engagement with the operator when the operator is in thesecond position.

3. The switch recited in claim 1 wherein the means for moving the detentmeans to detented position include externally operated manual means formoving the release member relative to the support when the operator isin the second position.

4. The switch recited in claim 1 wherein the locating means includesstop means on the support and resilient means biasing the release memberinto engagement with the stop means for locating the release member in apredetermined first position, the detent means including means carriedby the operator and engageable with the release member in the firstpositions of the operator and release member, the means for moving thedetent means to detented position including externally operated meansfor moving the release member relative to the support and against theresilient biasing means to a second position wherein the means carriedby the operator is engageable with the release member, the resilientbiasing means returning the release member and operator as a unit to thefirst position thereof.

5. An acceleration responsive switch comprising, in combination, asupport including a pair of spaced electrical contacts, a pair ofmembers mounted on the support for axial movement relative one anotherand the support between respective first and second positions, contactmeans mounted on one member and electrically connecting the spacedcontacts in the first position of the one member and disconnecting suchcontacts in the second position thereof, means biasing the one member tothe second position thereof, means normally locating the other member inthe first position thereof, the members each including generallyradially extending shoulder means located in axially spaced juxtaposedrelationship when the members are located in the same number positionand located out ofjuxtaposed relationship when the members are locatedin a different number position, ball means mounted on the one member formovement radially thereof between a first position in engagement withthe juxtaposed shoulder means to connect the one member to the othermember and locate the one member in the first position thereof againstthe action of the biasing means, and a second position out of engagementwith the shoulder means of the other member to permit movement of theone member to the second position thereof under the action ofthe biasingmeans. a seismic mass, means mounting the mass on the support formovement relative thereto when subjected to an acceleration pulse ofpredetermined amplitude and time, means on the mass engageable with theball means to normally hold the ball means in the first position thereofand being movable out of engagement with the ball means upon movement ofthe mass relative to the support to permit movement thereof to thesecond position, and means for moving the other member to the secondposition thereof when the one member is in the second position thereofto move the shoulder means of the other member into axially spacedjuxtaposed relationship and move the engageable means into engagementwith the ball means to move the ball means to the first positionthereof, the locating means returning the other member and the onemember as a unit therewith to the respective first positions thereof.

6. An acceleration responsive switch comprising, in combination, asupport including a pair of spaced electrical contacts, an operatormember mounted on the support for axial movement between first andsecond positions relative thereto, contact means mounted on the operatormember and electri cally connecting the spaced contacts in the firstposition of the operator member and disconnecting such contacts in thesecond position thereof, means biasing the operator member to the secondposition thereof, a release member mounted on the support for axialmovement relative to the operator member, means locating release memberin a first position thereof and resisting movement thereof to a secondposition thereof, the operator and release members each includinggenerally radially extending shoulder means located in axially spacedjuxtaposed relationship when the operator member is in the firstposition thereof and located out of juxtaposed relationship when theoperator member is in the second position thereof, ball means mounted onthe operator member for movement radially thereof between a firstposition in engagement with the juxtaposed shoulder means to locate theoperator member in the first position thereof against the action of thebiasing means and a second position out of engagement with the shouldermeans of the release member to permit movement of the operator member tothe second position thereof, seismic mass means mounted on the supportand moving when subjected to an acceleration pulse of predeterminedamplitude and time, means mounted on the seismic mass and engageablewith the ball means to normally hold the ball means in the firstposition thereof and moving out of engagement' with the ball means uponmovement of the seismic mass to permit movement of the ball means to thesecond position, and means for moving the release member to the secondposition thereof when the operator member is in the second positionthereof to move the shoulder means into axially spaced juxtaposedrelationship and move the means mounted on the seismic mass intoengagement with the ball means to move the ball means to the firstposition thereof, the

locating means for the release member returning the release member andthe operator member as a unit therewith to the respective firstpositions thereof.

1. An acceleration responsive switch, comprising, a support including apair of spaced electrical contacts, a release member movably mounted onthe support, means locating the release member in a predetermined firstposition, an operator mounted on the release member for axial movementrelative thereto between first and second positions, means biasing theoperator to the second position, detent means acting between theoperator and release member movable between detented and undetentedpositions and engageable in detented position with the operator to holdthe operator in the first position, a seismic mass movably mounted onthe support, means operatively connecting the mass to the detent meansfor movement of the detent means to undetented position to release theoperator for movement to the second position upon movement of theseismic mass relative to the support, magnetic means exerting a magneticflux of predetermined strength between the mass and support to retainthe seismic mass against movement relative to the support, anacceleration pulse of predetermined amplitude and time moving theseismic mass relative to the support against the flux of the magneticmeans to release the operator, contact means normally electricallyconnecting the spaced contacts, means disconnecting the contact meansand spaced contacts upon movement of the operator to second position,and means for moving the detent means to detented position in engagementwith the operator upon movement of the release member from thepredetermined first position when the operator is in the secondposition.
 2. The switch recited in claim 1 wherein the locating meansfor the release member includes resilient means holding the releasemember against stop means on the support, the resilient means returningthe release member to the predetermined first position thereof as a unitwith the release member upon movement of the detent means to detentedposition in engagement with the operator when the operator is in thesecond position.
 3. The switch recited in claim 1 wherein the means formoving the detent means to detented position include externally operatedmanual means for moving the release member relative to the support whenthe operator is in the second position.
 4. The switch recited in claim 1wherein the locating means includes stop means on the support andresilient means biasing the release member into engagement with the stopmeans for locating the release member in a predetermined first position,the detent means including means carried by the operator and engageablewith the release member in the first positions of the operator andrelease member, the means for moving the detent means to detentedposition including externally operated means for moving the releasemember relative to the support and against the resilient biasing meansto a second position wherein the means carried by the operator isengageable with the release member, the resilient biasing meansreturning the release member and operator as a unit to the firstposition thereof.
 5. An acceleration responsive switch comprising, incombination, a support including a pair of spaced electrical contacts, apair of members mounted on the support for axial movement relative oneanother and the support between respective first and second positions,contact means mounted on one member and electrically connecting thespaced contacts in the first position of the one member anddisconnecting such contacts in the second position thereof, meansbiasing the one member to the second position thereof, means normallylocating the other member in the first position thereof, the memberseach including generally radially extending shoulder means located inaxially spaced juxtaposed relationship when the members are located inthe same number position and located out of juxtaposed relationship whenthe members are located in a different number position, ball meansmounted on the one member for movement radially thereof between a firstposition in engagement with the juxtaposed shoulder means to connect theone member to the other member and locate the one member in the firstposition thereof against the action of the biasing means, and a secondposition out of engagement with the shoulder means of the other memberto permit movement of the one member to the second position thereofunder the action of the biasing means, a seismic mass, means mountingthe mass on the support for movement relative thereto when subjected toan acceleration pulse of predetermined amplitude and time, means on themass engageable with the ball means to normally hold the ball means inthe first position thereof and being movable out of engagement with theball means upon movement of the mass relative to the support to permitmovement thereof to the second position, and means for moving the othermember to the second position thereof when the one member is in thesecond position thereof to move the shoulder means of the other memberinto axially spaced juxtaposed relationship and move the engageablemeans into engagement with the ball means to move the ball means to thefirst position thereof, the locating means returning the other memberand the one member as a unit therewith to the respective first positionsthereof.
 6. An acceleration responsive switch comprising, incombination, a support including a pair of spaced electrical contacts,an operator member mounted on the support for axial movement betweenfirst and second positions relative thereto, contact means mounted onthe operator member and electrically connecting the spaced contacts inthe first position of the operator member and disconnecting suchcontacts in the second position thereof, means biasing the operatormember to the second position thereof, a release member mounted on thesupport for axial movement relative to the operator member, meanslocating release member in a first position thereof and resistingmovement thereof to a second position thereof, the operator and releasemembers each including generally radially extending shoulder meanslocated in axially spaced juxtaposed relationship when the operatormember is in the first position thereof and located out of juxtaposedrelationship when the operator member is in the second position thereof,ball means mounted on the operator member for movement radially thereofbetween a first position in engagement with the juxtaposed shouldermeans to locate the operator member in the first position thereofagainst the action of the biasing means and a second position out ofengagement with the shoulder means of the release member to permitmovement of the operator member to the second position thereof, seismicmass means mounted on the support and moving when subjected to anacceleration pulse of predetermined amplitude and time, means mounted onthe seismic mass and engageable with the ball means to normally hold theball means in the first position thereof and moving out of engagementwith the ball means upon movement of the seismic mass to permit movementof the ball means to the second position, and means for moving therelease member to the second position thereof when the operator memberis in the second position thereof to move the shoulder means intoaxially spaced juxtaposed relationship and move the means mounted on theseismic mass into engagement with the ball means to move the ball meansto the first position thereof, the locating means fOr the release memberreturning the release member and the operator member as a unit therewithto the respective first positions thereof.